Abstract
ABSTRACT: The objective of this study was to evaluate the effect of digestible methionine and cystine (Met + Cys) levels on the hematological and serum biochemical parameters of broiler chickens during the initial and growth stages. For this, 1,800 male chicks of the Coob 500 strain were used, with 900 chicks in the initial phase (1 to 21 days old) and 900 chicks in the growth phase (22 to 42 days old), distributed in a completely randomized design of five treatments with six replicates of 30 birds. The treatments consisted of 0.545, 0.616, 0.711, 0.782, and 0.853%; and 0.514, 0.571, 0.647, 0.704, and 0.761% digestible Met + Cys for “1 to 21” and “22 to 42” days of breeding, respectively. Results showed that digestible Met + Cys levels in broiler feed altered some hematological parameters (erythrocyte, hematocrit hemoglobin, total leukocytes, heterophile: lymphocyte) and serum biochemistry (uric acid, PST, total LDL, and TG). The digestible Met + Cys levels in the diet of broilers affected the hematological parameters and serum biochemistry, especially at higher levels. From the inclusion level 0.761 of Met + Cist in the broiler diet, red blood cells, hemoglobin and hematocrit changes begin to appear.
Highlights
The health conditions of birds are reflected by their blood constituents
The four main commercial sources of synthetic methionine used in broiler feed are DLmethionine (DL-Met) as a powder or liquid form as sodium salt (DL-methionine-Na) and methionine hydroxy analogue (MHA) as a powdered salt (MHACa) or in liquid form as a free acid (MHA-FA) (LEITE et al, 2009)
Hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and Total Plasma Proteins (TPP) values in the blood of the broilers were similar among treatments (Table 2)
Summary
The health conditions of birds are reflected by their blood constituents. Their evaluation is essential to determine the effect of the various conditions in which chickens are being bred, since several factors, including metabolism (BORSA, 2006; MINAFRA et al, 2010) affect the results. Methionine is the first limiting factor in corn and soybean meal-based diets, as they are deficient in that amino acid (WEN et al, 2014; ZHANG et al, 2015). Several studies have been conducted to evaluate the performance and determine the nutritional requirements for methionine in broiler chickens fed with corn and soybean based diets (LEITE et al, 2009; LUMPKINS et al, 2007; GOULART et al, 2011; TAVERNARI et al, 2014; CONDE-AGUILERA et al, 2016). The effects of Met + Cys levels in the diet and the sources of methionine available on the chick health market are not well known
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